1. The Field of the Invention
This invention relates generally to exercise apparatus and more specifically to a novel apparatus for exercising which combines the principles of isometrics and isotonics.
2. The Prior Art
Increasingly, individuals and groups are becoming conscientious of exercising and other health related habits, and making substantial efforts to improve the same. Responsive to this increased awareness, the health and physical fitness industries have grown tremendously in the last several years. New exercise products are being introduced continuously.
Virtually all resistance-type exercise devices and apparatus use one of three basic resistance principles. The first of these is isometrics, which is a static form of exercise wherein the joints are moved at a constant speed (0 degrees per second) against a constant resistance, that is, with no observable joint movement. For example, pushing the palms of the hands against one another is an isometric exercise. Studies indicate that isometric exercise increases strength primarily at the specific angle assumed by the joint when force is applied.
The second form of resistance is isotonics and involves movement of a joint throughout a range of motion against a constant resistance. The best example of isotonic exercise is the use of barbells or similar free weights. With traditional isotonics, there is no way to accommodate for biomechanical leverage changes that increase and decrease muscular efficiency throughout the range of motion. Therefore, the dynamically contracting muscle is only loaded maximally at its weakest point in the range of motion.
The third basic type of resistance exercise is isokinetics and entails exercise performed at a constant speed with totally accommodating resistance throughout the entire range of motion. This form of exercise requires specially designed, complex, and expensive equipment, and usually requires constant supervision. Therefore, exercise apparatus utilizing the principle of isokinetics are generally not well suited to the individual who may wish to exercise within the confines of his own home or who cannot afford the great expense of such apparatus.
While a great number of exercise devices and apparatus are known which utilize either the isometric or isotonic method of exercise, there does not appear to be any apparatus in the exercise or therapy field which combines these two principles. A great advantage would be gained thereby, since both of these principles have distinct advantages. For example, isometric exercises provide the following important advantages: less joint irritation since there is no joint motion, increase of static muscular strength, reduction in swelling of joints, and isometric exercises can be performed anywhere in relatively short periods of time.
Similarly, some of the advantages of isotonic exercises are: ready availability, provides motivation by achievement (the user is able to lift more weight as muscles are strengthened), improves muscular endurance, is objectively documentable, and increases muscular strength with relatively few repetitions.
In addition to combining these desirable advantages, an exercise apparatus utilizing both isometrics and isokinetics would obviate the above-mentioned problem associated with isotonic exercise of maximally loading the dynamically contracting muscle at only its weakest point. Instead, the apparatus could be adjusted such that maximal loading could occur at any of the several points along its limited range of motion. Thus, it becomes clear that an exercise apparatus combining the advantages of both isometric and isotonic exercise would be a great advance in the art. Moreover, such an apparatus would have great benefits as a physical therapy device for use by those who have suffered an injury or who have reduced capacity for exercise.